Device for feeding webs in recording instruments

ABSTRACT

Web-feeding device including web supply and takeup reservoirs mounted for movement to respectively supply and take up the web longitudinally of the web, a web drive mounted intermediate the reservoirs longitudinally of the web and being actuable to move the web and having an inertia incident to that movement less than the inertia characterizing at least one of the reservoirs in respective movement to supply and take up the web; and a dual loop control in which a pair of loop guides are mounted on a support in spaced relation to each other with the loops extending in generally opposite directions, one guide being intermediate of the supply reservoir and the web drive in a direction longitudinal of the web, the other guide being so intermediate of the web drive and the takeup reservoir, the support being movable toward and away from a generally central position.

United States Patent Reginald E. Freeman High Wycombe, Buckinghamshire,

[72] Inventor England [21] Appl. No. 843,930

[22] Filed July 23, 1969 [45] Patented Oct. 12, 1971 [7 3] Assignee Instron Corporation Canton, Mass.

[32] Priority July 26, 1968 [33] Great Britain [54] DEVICE FOR FEEDING WEBS IN RECORDING [56] References Cited UNITED STATES PATENTS 2,656,129 10/1953 De Turk et a] 242/190 3,217,996 11/1965 Bemier 242/188 Primary Examiner-Leonard D. Christian AttorneyWilliam W. Rymer ABSTRACT: Web-feeding device including web supply and takeup reservoirs mounted for movement to respectively supply and take up the web longitudinally of the web, a web drive mounted intermediate the reservoirs longitudinally of the web and being actuable to move the web and having an inertia incident to that movement less than the inertia characterizing at least one of the reservoirs in respective movement to supply and take up the web; and a dual loop control in which a pair of loop guides are mounted on a support in spaced relation to each other with the loops extending in generally opposite directions, one guide being intermediate of the supply reservoir and the web drive in a direction longitudinal of the web, the other guide being so intermediate of the web drive and the takeup reservoir, the support being movable toward and away from a generally central position.

DEVICE FOR FEEDING WEBS IN RECORDING INSTRUMENTS This invention relates to feeding webs in recording instruments.

A primary object of the invention is to provide for highly responsive and sensitive control of web feed rate, including the ability to rapidly accelerate the web, despite the inertia incident to web supply or takeup reservoir movement. Other objects are to provide a compact, simple, and inexpensive web feed.

The invention features web supply and takeup reservoirs mounted for movement to respectively supply and take up the web longitudinally of the web, a web drive mounted intermediate the reservoirs longitudinally of the web and being actuable to move the web and having an inertia incident to that movement less than the inertia characterizing at least one of the reservoirs in respective movement to supply and take up the web; and a dual loop control in which a pair of loop guides are mounted on a support in spaced relation to each other with the loops extending in generally opposite directions, one guide being intermediate of the supply reservoir and the web drive in a direction longitudinal of the web, the other guide being so intermediate of the web drive and the takeup reservoir, the support being movable toward and away from a generally central position. In preferred embodiments a web guide is mounted intermediate the web drive and one of the reservoirs longitudinally of the web to change generally the longitudinal direction of movement of the web therearound; the web drive and web guide are respectively driven and idler rollers; the loop guides are idler rollers mounted on a slider movable along a line parallel to the web stretch between the web drive and web guide; and the bracket carries a wiper that slides over a resistor, the wiper and resistor acting as a potentiometer in a circuit for control of the rate of web feed out of the supply reservoir to tend to keep the loop guide support at its generally central position.

Other objects, features, and advantages will appear from the following description of a preferred embodiment, taken together with the attached drawing showing schematically portions of a web feeding device.

As shown in the drawing, supply roll 10, takeup roll 12, web drive roller 14, and idler rollers 16, 18, 20 are rotatably supported on the frame 22. A slide assembly 24 comprising two loop guide rollers 26, 28 rotatably attached to slider 30, is translatably supported to permit motion in the direction of arrows 32, 33. Paper web 40 extends from the supply roll over the idler roller 18, loop guide roller 26, web drive roller 14, idler roller 16, loop guide roller 28, and idler roller 20 successively, to takeup roll 12. Spring brush 42 is attached to slider 30 and makes sliding contact with resistance wire 44 which is supported by wire support 46, made of nonconductive material. Wire support 46 is adjustably attached to the frame 22 permitting adjustment of the contact pressure between the spring brush 42 and the resistance wire 44. Drive belt 50 loops around supply spool 52 attached concentrically to supply roll 10, takeup spool 54 attached concentrically through a clutch to takeup roll 12, feed drive spool 56, and idler spool 58 mounted rotatably on the frame 22. Feed drive spool 56 is driven in rotation by feed motor 60 attached to the frame 22. Electrical circuitry (not shown) is provided, including brush 42 and wire 44 which together act as a potentiometer, to control the speed of motor 60 so that the speed decreases as slide brush 42 moves along wire 44 in the direction of arrow 33.

The inertia incident to rotation of either roller 14 or 16 is less than that incident to rotation of either roll 10 or 12.

In operation with a conventional pen recording device 88 mounted to record data on the stretch 90 of web between rollers l4 and 16, and with motor 60 turned on, roller 14 is driven at a rate sufficient to advance the web longitudinally along stretch 90 at the desired rate. So long as that rate of web advance is the same as the rate at which the web is fed from supply roll 10, slider 30 will remain stationary. As the web drive roller 14 is driven in the direction of arrow 78, web will be drawn from loop 80 and paid into loop 82. At the same time supply roll 10 pays web into loop 80 and takeup roll 12 draws webfrom loop 82.

If, however, the motion of web drive roller 14 draws more web from loop than the motion of the feed drive spool 56 pays into loop 80, loop 80 will shorten while loop 82 will lengthen and the slide assembly 24 will move in the direction of arrow 32. The electrical signal indicative of the position of the slider 30 will consequently change and, acting through the control circuitry, cause the feed drive spool to pay web into loop 80 (and draw it from loop 82) more rapidly. If less web is drawn from loop 80 than is paid in, the action is reversed. The rotations of supply roll 10 and takeup roll 12 are thus adjusted to the demand of the web drive roller 14.

Since the rate of rotation of low-inertia roller 14 can be changed more rapidly than can that of the supply or takeup rolls (even when the inertia of slider assembly 24 is taken into account), highly sensitive control of web speed is thus provided.

Other embodiments (e.g., in which the supply and takeup rolls are stopped for each recording cycle, and slider assembly 24 moves in full correspondence to the web advance along stretch will occur to those skilled in the art and are within the following claims.

What is claimed is:

1,. A recording web-feeding device which comprises:

a web supply reservoir mounted for movement to supply said web in a direction longitudinal of said web,

a web takeup reservoir mounted for movement to take up said web in a direction longitudinal of said web,

a web drive mounted intermediate of said web supply reservoir and said web takeup reservoir longitudinally of said web,

said web drive being actuatable to move said web and having an inertia incident to said movement less than the inertia characterizing at least one of said web supply reservoir and said web takeup reservoir in respective movement to supply and take up said web,

a pen recorder mounted intermediate said reservoirs to produce a trace on said web, and

a dual loop control,

said dual loop control comprising a first loop guide, a second loop guide, and a loop guide support supporting the loop guides in spaced relation to each other and with the loops extending in generally opposite directions with said first loop guide intermediate of said web supply reservoir and said web drive in a direction longitudinal of said web and said second loop guide intermediate of said web drive and said web takeup reservoir in a direction longitudinally of said web, said loop guide support being movable toward and away from a generally central position to permit the rate of movement of said web past said pen recorder to be governed solely by said web drive.

2. The device of claim I wherein a web guide is mounted intermediate said web drive and one of said reservoirs longitudinally of said web to change generally the longitudinal direction of movement of said web therearound.

3. The device of claim 2 wherein said web drive and said web guide are respectively driven and idler rollers.

4. The device of claim 1 wherein said loop guides are mounted on a slider movable along a line parallel to a stretch of web adjacent said web drive.

5. The device of claim 4 wherein said stretch is downstream of said web drive.

6. The device of claim 5 wherein said stretch is between said web drive and said web guide.

7 The device of claim 4 wherein said loop guides each com prises a single idler roller.

8. The device of claim I further comprising a control responsive to the position of said support relative to said generally central position, to control said movement of said reservoirs to tend to keep said support at said generally central position.

9. The device of claim 8 wherein said control comprises a wiper carried by said support for linear movement and a resistor mounted adjacent said wiper to effectively form a potentiometer. 

1,. A recording web-feeding device which comprises: a web supply reservoir mounted for movement to supply said web in a direction longitudinal of said web, a web takeup reservoir mounted for movement to take up said web in a direction longitudinal of said web, a web drive mounted intermediate of said web supply reservoir and said web takeup reservoir longitudinally of said web, said web drive being actuatable to move said web and having an inertia incident to said movement less than the inertia characterizing at least one of said web supply reservoir and said web takeup reservoir in respective movement to supply and take up said web, a pen recorder mounted intermediate said reservoirs to produce a trace on said web, and a dual loop control, said dual loop control comprising a first loop guide, a second loop guide, and a loop guide support supporting the loop guides in spaced relation to each other and with the loops extending in generally opposite directions with said first loop guide intermediate of said web supply reservoir and said web drive in a direction longiTudinal of said web and said second loop guide intermediate of said web drive and said web takeup reservoir in a direction longitudinally of said web, said loop guide support being movable toward and away from a generally central position to permit the rate of movement of said web past said pen recorder to be governed solely by said web drive.
 2. The device of claim 1 wherein a web guide is mounted intermediate said web drive and one of said reservoirs longitudinally of said web to change generally the longitudinal direction of movement of said web therearound.
 3. The device of claim 2 wherein said web drive and said web guide are respectively driven and idler rollers.
 4. The device of claim 1 wherein said loop guides are mounted on a slider movable along a line parallel to a stretch of web adjacent said web drive.
 5. The device of claim 4 wherein said stretch is downstream of said web drive.
 6. The device of claim 5 wherein said stretch is between said web drive and said web guide. 7 The device of claim 4 wherein said loop guides each comprises a single idler roller.
 8. The device of claim 1 further comprising a control responsive to the position of said support relative to said generally central position, to control said movement of said reservoirs to tend to keep said support at said generally central position.
 9. The device of claim 8 wherein said control comprises a wiper carried by said support for linear movement and a resistor mounted adjacent said wiper to effectively form a potentiometer. 